Digital radiography versus conventional radiography in chest imaging: diagnostic performance of a large-area silicon flat-panel detector in a clinical CT-controlled study

OBJECTIVE

The objective of this study was to compare the diagnostic performance of a digital large-area silicon flat-panel detector with that of a conventional screen-film system in clinical chest imaging using abnormal findings documented by CT as the reference standard.

SUBJECTS AND METHODS

Eighty patients (46 men and 34 women; age range,18-91 years; mean age, 63 years) who underwent CT of the chest were examined with the new digital radiography system, which is based on a 43 x 43 cm silicon flat-panel detector, and with a conventional screen-film system, which is used routinely in clinical practice. Posteroanterior and lateral radiographs were obtained. Four radiologists analyzed the digital and conventional images separately for chest abnormalities and rated the images using a five-level scale of confidence; CT was used as the reference standard. Diagnostic value was assessed using receiver operating characteristic curves for each abnormality.

RESULTS

No significant differences were found between the area under the receiver operating characteristic curve of the digital and that of the conventional radiography method for almost all investigated criteria. The only exception was mediastinal abnormalities, for which the digital method provided better results than the conventional method (p < 0.05).

CONCLUSION

The diagnostic performance of the new large-area silicon flat-panel detector is equivalent or superior to that of the conventional screen-film system for clinical chest imaging and can replace conventional radiography systems. This new technology offers transmission and storage possibilities inherent to digital radiology that would facilitate daily practice and reduce the initial high costs in the long-term.

HSV-1-based vectors for gene therapy of neurological diseases and brain tumors: part I. HSV-1 structure, replication and pathogenesis

The design of effective gene therapy strategies for brain tumors and other neurological disorders relies on the understanding of genetic and pathophysiological alterations associated with the disease, on the biological characteristics of the target tissue, and on the development of safe vectors and expression systems to achieve efficient, targeted and regulated, therapeutic gene expression. The herpes simplex virus type 1 (HSV-1) virion is one of the most efficient of all current gene transfer vehicles with regard to nuclear gene delivery in central nervous system-derived cells including brain tumors. HSV-1-related research over the past decades has provided excellent insight into the structure and function of this virus, which, in turn, facilitated the design of innovative vector systems. Here, we review aspects of HSV-1 structure, replication and pathogenesis, which are relevant for the engineering of HSV-1-based vectors.

The DNA sequences of T-DNA junctions suggest that complex T-DNA loci are formed by a recombination process resembling T-DNA integration

After Agrobacterium-mediated plant transformation, multiple T-DNAs frequently integrate at the same position in the plant genome, resulting in the formation of inverted and direct repeats. Because these inverted repeats cannot be amplified and analyzed by PCR, Arabidopsis root cells were co-transformed with two different T-DNAs with distinct sequences adjacent to the T-DNA borders. Nine direct or inverted T-DNA border junctions were analyzed at the sequence level. Precise end-to-end fusions were found between two right border ends, whereas imprecise fusions and filler DNA were present in T-DNA linkages containing a left border end. The results suggest that end-to-end ligation of double-stranded T-DNAs occurs especially between right T-DNA ends and that illegitimate recombination on the basis of microhomology, deletions, repair activities and insertions of filler DNA is involved in the formation of left border T-DNA junctions. Therefore, a similar illegitimate recombination mechanism is proposed that is involved in the formation of complex T-DNA inserts as well as in the integration of the T-DNA in the plant genome.

HSV-1-based vectors for gene therapy of neurological diseases and brain tumors: part II. Vector systems and applications

Many properties of HSV-1 are especially suitable for using this virus as a vector to treat diseases affecting the central nervous system (CNS), such as Parkinson's disease or malignant gliomas. These advantageous properties include natural neurotropism, high transduction efficiency, large transgene capacity, and the ability of entering a latent state in neurons. Selective oncolysis in combination with modulation of the immune response mediated by replication-conditional HSV-1 vectors appears to be a highly promising approach in the battle against malignant glioma. Helper virus-free HSV/AAV hybrid amplicon vectors have great promise in mediating long-term gene expression in the PNS and CNS for the treatment of various neurodegenerative disorders or chronic pain. Current research focuses on the design of HSV-1-derived vectors which are targeted to certain cell types and support transcriptionally regulatable transgene expression. Here, we review the recent developments on HSV-1-based vector systems and their applications in experimental and clinical gene therapy protocols.

Maternal care and attachment security in ordinary and emergency contexts

One of the foundations of attachment theory is the notion that early care plays a key role in determining the quality of child-caregiver attachment relationships. Studies have consistently shown relations between maternal sensitivity and infant security. Further research is required to resolve issues arising from modest correlations, focus on research in stressful as opposed to ordinary contexts, and questions about the generality of results across cultures and social contexts and about the context specificity of caregiving behavior. This article addressed these issues in 2 studies of child care in home and hospital contexts. Q-sort scores derived from extended naturalistic observations were used. Results are discussed in terms of links between methodology and effect sizes, the generality of links between maternal care and child security, the need for further research on caregiving in ordinary and emergency situations, and the context sensitivity of maternal behavior.

Patterns of failure in endometrial carcinoma stage IB grade 3 and IC patients treated with postoperative vaginal vault brachytherapy

OBJECTIVE

The vagina is the most common site of locoregional failure in surgical stage IB, IC, and II (occult) endometrial adenocarcinoma. The objective of this study is to evaluate the therapeutic efficacy of vaginal vault brachytherapy alone for surgical stage I patients with high-risk features.

MATERIALS AND METHODS

The study group consists of high-risk stage I patients with either stage IB grade (G) 3 or any grade IC disease. From February 1991 to August 1997, 124 patients with endometrial carcinoma were treated postoperatively with high-dose-rate vaginal vault brachytherapy as the only adjuvant treatment. All patients were surgically staged. Among them, 38 patients were identified as high risk. Twelve patients had stage IBG3, 14 had ICG1, 9 had ICG2, and 3 had ICG3 disease. The median age was 67 years (range 41 to 86 years). A dose of 21 Gy in three fractions of 7 Gy each was delivered to a prescription depth of 0.5 cm from the surface of the vaginal applicator using high-dose-rate brachytherapy.

RESULTS

The median follow-up was 30 months (range 7 to 91 months). No patient has developed a vaginal or pelvic recurrence. Three patients developed tumor recurrence in the upper abdomen at 11, 18, and 37 months. Two of the three patients with recurrent disease also had history of breast cancer. In one patient, breast cancer was diagnosed 4.8 years prior and in the second 3 years subsequent to the diagnosis of endometrial cancer. The 5-year actuarial overall survival and disease-free survival are 93 and 87%, respectively. There was no treatment-related grade 3 or 4 morbidity observed.

CONCLUSIONS

For patients with surgical stage IBG3 and IC, excellent local control and minimal morbidity has been observed with the selective use of vaginal brachytherapy alone. Further studies and longer follow-up are warranted.

Caveolin-1 modulates the activity of the volume-regulated chloride channel

1. Caveolae are small invaginations of the plasma membrane that have recently been implicated in signal transduction. In the present study, we have investigated whether caveolins, the principal protein of caveolae, also modulate volume-regulated anion channels (VRACs). 2. ICl,swell, the cell swelling-induced chloride current through VRACs, was studied in three caveolin-1-deficient cell lines: Caco-2, MCF-7 and T47D. 3. Electrophysiological measurements showed that ICl, swell was very small in these cells and that transient expression of caveolin-1 restored ICl,swell. The caveolin-1 effect was isoform specific: caveolin-1beta but not caveolin-1alpha upregulated VRACs. This correlated with a different subcellular distribution of caveolin-1alpha (perinuclear location) from caveolin-1beta (perinuclear and peripheral). 4. To explain the modulation of ICl, swell by caveolin-1 we propose that caveolin increases the availability of VRACs in the plasma membrane or, alternatively, that it plays a crucial role in the signal transduction cascade of VRACs.

Improved performance of seroconversion with a 4th generation HIV antigen/antibody assay

Recently a new fourth generation microELISA for large scale blood screening has been described in which HIV p24 Ag detection was integrated in an anti-HIV-1/-2 and anti-HIV-1 group O assay based on a direct assay format: (Vironostika HIV Uni-Form II Ag/Ab (Van Binsbergen et al., (1998)). When compared to the third generation a-HIV assay (Vironostika HIV Uni-Form II plus O), the seroconversion window was narrowed with more than one week. A more precise window estimation based on seroconversion series with short sampling time intervals of up to 7 days, is described in parallel with that for the single HIV p24 Ag assay. It was found with 10 relevant seroconversion series that the HIV p24 Ag assay closes the seroconversion window with 6.2 days as compared to the 3rd generation a-HIV assay, while a window reduction of 4 days was found with Vironostika HIV Uni-Form II Ag/Ab. These seroconversion data show that with the new assay two-thirds of the current p24 Ag window is closed. There was no statistical difference in seroconversion sensitivity between the HIV p24 Ag and the new assay format. An extended evaluation of the new assay with subtype HIV-1 M and group O p24 Ag strains and with anti-HIV antibodies obtained from individuals infected with different HIV-1 subtypes showed that all subtypes of HIV-1 M and HIV-1 group O p24 antigen were detected as well as of HIV antibody.

Optimizing electrode sites for segmental bioimpedance measurements

Recent advances in the application of bioelectrical impedance analysis (BIA) have indicated that a more accurate approach to the estimation of total body water is to consider the impedance of the various body segments rather than simply that of the whole body. The segmental approach necessitates defining and locating the physical demarcation between both the trunk and leg and the trunk and arm. Despite the use of anatomical markers, these points of demarcation are difficult to locate with precision between subjects. There are also technical problems associated with the regional dispersion of the current distribution from one segment (cylinder) to another of different cross-sectional area. The concept of equipotentials in line with the proximal aspects of the upper (and lower) limbs along the contralateral limbs was investigated and, in particular, the utility of this concept in the measurement of segmental bioimpedance. The variation of measured segmental impedance using electrode sites along these equipotentials was less than 2.0% for all of the commonly used impedance parameters. This variation is approximately equal to that expected from biological variation over the measurement time. It is recommended that the electrode sites, for the measurement of segmental bioelectrical impedance in humans, described herein are adopted in accordance with the proposals of the NIH Technology Assessment Conference Statement.

Functional coexpression of HSV-1 thymidine kinase and green fluorescent protein: implications for noninvasive imaging of transgene expression

Current gene therapy technology is limited by the paucity of methodology for determining the location and magnitude of therapeutic transgene expression in vivo. We describe and validate a paradigm for monitoring therapeutic transgene expression by noninvasive imaging of the herpes simplex virus type 1 thymidine kinase (HSV-1-tk) marker gene expression. To test proportional coexpression of therapeutic and marker genes, a model fusion gene comprising green fluorescent protein (gfp) and HSV-1-tk genes was generated (tkgfp gene) and assessed for the functional coexpression of the gene product, TKGFP fusion protein, in rat 9L gliosarcoma, RG2 glioma, and W256 carcinoma cells. Analysis of the TKGFP protein demonstrated that it can serve as a therapeutic gene by rendering tkgfp transduced cells sensitive to ganciclovir or as a screening marker useful for identifying transduced cells by fluorescence microscopy or fluorescence-activated cell sorting (FACS). TK and GFP activities in the TKGFP fusion protein were similar to corresponding wild-type proteins and accumulation of the HSV-1-tk-specific radiolabeled substrate, 2'-fluoro-2'-deoxy-1beta-D-arabinofuranosyl-5-iodo-uracil (FIAU), in stability transduced clones correlated with gfp-fluorescence intensity over a wide range of expression levels. The tkgfp fusion gene itself may be useful in developing novel cancer gene therapy approaches. Valuable information about the efficiency of gene transfer and expression could be obtained by non-invasive imaging of tkgfp expression with FIAU and clinical imaging devices (gamma camera, positron-emission tomography [PET], single photon emission computed tomography [SPECT]), and/or direct visualization of gfp expression in situ by fluorescence microscopy or endoscopy.

Combined HSV-1 recombinant and amplicon piggyback vectors: replication-competent and defective forms, and therapeutic efficacy for experimental gliomas

BACKGROUND

The versatility of HSV-1 vectors includes large transgene capacity, selective replication of mutants in dividing cells, and availability of recombinant virus (RV) and plasmid-derived (amplicon) vectors, which can be propagated in a co-dependent, 'piggyback', manner.

METHODS

A replication-defective piggyback vector system was generated in which the amplicon carries either of two genes essential for virus replication, IE2 (ICP27) or IE3 (ICP4), as well as lacZ; the RV is deleted in both these genes, and vector stocks are propagated in cells transfected with one of the complementary genes. In the replication-competent system, the amplicon carries the IE2 and lacZ; the RV had a large deletion in the IE2; and stocks are propagated in untransfected cells. Titers over successive passages, recombination between amplicon and RV, and the structural integrity of vector genomes were evaluated. The replication-competent system was tested for therapeutic efficacy in subcutaneous 9L gliosarcoma tumors in nude mice with activation of ganciclovir via the viral HSV-thymidine kinase gene.

RESULTS

Both systems generated high titer amplicon vectors (about 10(7) tu/ml) and amplicon:RV ratios (0.6-3.0). No replication-competent RV was generated in either system. The replication-defective system showed low toxicity and increased packaging efficiency of amplicon vectors, as compared to single mutant RV helper virus. The replication-competent system allowed co-propagation of amplicon and RV; injection into tumors followed by ganciclovir treatment inhibited tumor growth without systemic toxicity.

CONCLUSION

New replication-defective and replication-competent piggyback HSV, vector systems allow gene delivery via amplicon vectors with reduced toxicity and co-propagation of both RV and amplicon vectors in target cells, with effective tumor therapy via focal virus replication and pro-drug activation.

Bioimpedance: is it a predictor of true water volume?

Bioelectrical impedance analysis (BIA) has been reported to be insensitive to changes in water volumes in individual subjects. This study was designed to investigate the effect on the intra- and extracellular resistances (Ri and Re) of the segments of subjects for whom body water was changed without significant change to the total amount of electrolyte in the respective fluids. Twelve healthy adult subjects were recruited. Ri and Re of the leg, trunk, and arm of the subjects were determined from BIA measures prior to commencement of two separate studies that involved intervention, resulting in a loss/gain of body water effected either by a sauna followed by water intake (study 1) or by ingestion (study 2). Ri and Re of the segments were also determined at a number of times following these interventions. The mean change in body water, expressed as a percentage of body weight, was 0.9% in study 1 and 1.25% in study 2. For each study, the results for each subject were normalized for each limb to the initial (prestudy) value and then the normalized results for each segment were pooled for all subjects. ANOVA of these pooled results failed to demonstrate any significant differences between the normalized mean values of Ri or Re of the segments measured through the course of each study. The failure to detect a change in Ri or Re is explained in terms of the basic theory of BIA.

Assessing environmental exposure to PCBs among Mohawks at Akwesasne through the use of geostatistical methods

The Mohawk Nation at Akwesasne is a Native American community located along the St. Lawrence River in New York State, Ontario, and Quebec. One component of a multiphase human health study was to assess the impact of different pathways of human exposure resulting from the off-site migration of polychlorinated biphenyl (PCB) contamination in this area. This paper illustrates how mapped residential information and environmental sampling data can be united to assist in exposure assessment for epidemiologic studies using geographic information system (GIS) technology and statistical methods. A proportional sampling scheme was developed to collect 119 surface soils. Using a method of cross validation, the average estimated error can be computed and the best estimator can be selected. Seven spatial methods were examined to estimate surface soil PCB concentrations; the lowest relative mean error was 0.42% for Inverse 3 nearest neighbor weighted according to the inverse distance, and the highest relative mean error was 4.4% for Voronoi polygons. Residual plots indicated that all methods performed well except near some of the sampling points that formed the outer boundaries of the sampling distribution.

Local fish consumption and serum PCB concentrations among Mohawk men at Akwesasne

A study was conducted to assess local fish consumption patterns and their relationship to concentrations of total polychlorinated biphenyls (PCBs) in the serum of Mohawk men residing near three hazardous waste sites. From 1992 to 1995, 139 men were interviewed and donated a 20-ml venous blood sample. The results indicated that the men ate a mean of 21.2 local fish meals during the past year, compared with annual means of 27.7 meals 1-2 years before and 88.6 meals more than 2 years before (P<0.001 for test of trend). This change is probably a consequence of advisories issued against the consumption of local fish, since 97% of the men were aware of the advisories and two-thirds had changed their behavior as a result. Multiple regression analysis revealed that serum PCB levels increased with age (beta=0.036, P<0.001) and local fish consumption (beta=0.088, P=0.006). The data suggest that local fish consumption has contributed to body burdens in this population and that the advisories have been effective in modifying local fish consumption habits.

High level accumulation of single-chain variable fragments in the cytosol of transgenic Petunia hybrida

The accumulation of five murine single-chain variable fragments, binding to dihydroflavonol 4-reductase, was analyzed in transgenic Petunia hybrida plants. The five scFv-encoding sequences were cloned in an optimized plant transformation vector for expression in the cytosol under control of the 35S promoter. In a transient expression assay we found that the scFv expression levels were reproducible and correlated with those in stably transformed petunia. Our results show that accumulation in the cytosol strongly depends on the intrinsic properties of the scFv fragment. Three of the five scFv fragments accumulated to unexpectedly high levels in the cytosol of the primary transformants, but no phenotypic effect could be detected. Experimental results indicate that one of the scFv fragments accumulated in the cytosol to 1% of the total soluble protein as a functional antigen-binding protein in the absence of disulphide bonds. This observation supports the idea that certain antibody fragments do not need disulphide bonds to be stable and functional. Such scFv scaffolds provide new opportunities to design scFv fragments for immunomodulation in the cytosol.

Gene silencing results in instability of antibody production in transgenic plants

The stability of antibody and Fab expression was assessed in five different homozygous transgenic Arabidopsis lines. Each of these lines showed silencing of the transgenes that encode the antibody polypeptides, leading to instability of antibody production. However, each line had a different and specific instability profile. The characteristic variation in the level of antibody accumulation in each line as a function of developmental stage indicated that the T-DNA integration pattern played a role in triggering silencing, and also that the history and the integration position of simple transgene loci can influence the susceptibility to epigenetic silencing. In different lines with low antibody accumulation levels, methylation was found either in the promoter alone, in both the promoter and the transcribed region, in the transcribed region only, or in the transcribed region and downstream sequences. In conclusion, our data suggest that epigenetic effects result in different transgene expression profiles in each of the five Arabidopsis lines analyzed.

Strongly enhanced sensitivity of a direct anti-HIV-1/-2 assay in seroconversion by incorporation of HIV p24 ag detection: a new generation vironostika HIV Uni-Form II

The clinical sensitivity of the current anti-HIV assays is based for an important part on their reactivity with seroconversion panels. The most sensitive assay closes the seroconversion window as much as possible, thereby reducing the risk of transmitting false negative donations obtained from individuals infected recently. Because of the absence of anti-HIV antibodies during the early phase of infection, the seroconversion window can be narrowed partially by detection of HIV p24 Ag. To achieve this, the highest affinity anti-p24 binding antibodies were selected with BlAcore and applied in a direct assay format. To achieve optimal conditions for the anti-HIV part of the assay the HIV specific antigens viral HIV-1 gp160, HIV-2 gp36 and HIV-1 group O gp41 peptides were used. These antigens and antibodies were applied for microELISA coating as well as in the conjugate pearl, which is present in the well of the microELISA plate. The (analytical) anti-HIV-1/-2 and anti-HIV-1 group O sensitivity of this new assay, Vironostika HIV Uni-Form II Ag/Ab, is at least at the level of the current Vironostika HIV Uni-Form II plus O. When compared to the Vironostika HIV Uni-Form II plus O, the seroconversion window is narrowed by 1-2 weeks due to the incorporation of HIV p24 Ag detection. The level of reactivity of the anti-HIV and HIV Ag detection part can be improved by about a factor 2 by applying continuous shaking during sample incubation. Initial studies suggested that the specificity of the assay is identical to that of the Vironostika HIV Uni-Form II plus O, namely > 99.9%. Monitoring of proper execution of the assay handling steps was facilitated by implementing a purple dye in the conjugate pearl. Colourless specimen diluent changes into a green fluid upon dissolving of the conjugate pearl and turns subsequently into blue/purple upon sample addition. These visual changes can also be determined by spectrophotometric measurement at 620 nm.

High-dose busulfan, melphalan and thiotepa followed by autologous peripheral blood stem cell (PBSC) rescue in patients with advanced stage III/IV ovarian cancer

The purpose of this study was to evaluate the efficacy of high-dose chemotherapy (HDC) with busulfan, melphalan and thiotepa (BUMELTT) followed by autologous PBSC infusion in treating patients with advanced ovarian cancer. Thirty-one patients, 18 with stage III/IIIc and 13 with stage IV ovarian cancer, were treated with BU (12 mg/kg), MEL (100 mg/m2) and TT (500 mg/m2) and autologous PBSC rescue. Fifteen patients were in clinical complete remission (CR) at treatment; 11 had platinum-sensitive disease. Sixteen patients were not in CR; two had platinum-sensitive disease. The probabilities of overall survival (OS), event-free survival (EFS) and relapse (R) for all patients at 18 months were 0.57, 0.30 and 0.63; for patients in CR, the rates were 0.87, 0.44 and 0.49 and for patients not in CR, 0.38, 0.13 and 0.81. Two patients (6.5%) died of treatment-related causes. Among the 13 patients with platinum-sensitive disease, all are still alive, with seven having relapsed 129-1021 days after PBSC infusion. OS, EFS and R were 1.00, 0.52 and 0.48. Of the 18 patients with platinum-resistant disease, four remain alive (two in remission). Six patients did not respond and eight relapsed from days 104-429. The OS, EFS and R were 0.33, 0.11 and 0.78. We conclude that BUMELTT is well tolerated in patients with advanced ovarian cancer and results are equivalent to other published HDC regimens.

The conjugal intermediate of plasmid RSF1010 inhibits Agrobacterium tumefaciens virulence and VirB-dependent export of VirE2

Agrobacterium tumefaciens causes crown gall disease by transferring oncogenic, single-stranded DNA (T strand), covalently attached to the VirD2 protein, across the bacterial envelope into plant cells where its expression results in tumor formation. The single-stranded DNA binding protein VirE2 is also transferred into the plant cell, though the location at which VirE2 interacts with the T strand is still under investigation. The movement of the transferred DNA and VirE2 from A. tumefaciens to the plant cell depends on the membrane-localized VirB and VirD4 proteins. Further, the movement of the IncQ broad-host-range plasmid RSF1010 between Agrobacterium strains or from Agrobacterium to plants also requires the virB-encoded transfer system. Our earlier studies showed that the presence of the RSF1010 plasmid in wild-type strains of Agrobacterium inhibits both their virulence and their capacity to transport VirE2, as assayed by coinfection with virE mutants. Here we demonstrate that the capacity to form a conjugal intermediate of RSF1010 is necessary for this inhibition, suggesting that the transferred form of the plasmid competes with the VirD2-T strand and/or VirE2 for a common export site.

Agrobacterium tumefaciens transformation and cotransformation frequencies of Arabidopsis thaliana root explants and tobacco protoplasts

In view of the recent finding that different T-DNAs tend to ligate and integrate as repeats at single chromosomal positions, the frequency of transformation and cotransformation was determined during cocultivation of Arabidopsis thaliana root explants and Nicotiana tabacum protoplasts with two Agrobacterium strains. The transformation frequency of unselected A. thaliana shoots was lower than 1% whereas that of cocultivated tobacco protoplasts was approximately 18%. The cotransformation frequencies, defined as the frequencies with which cells transformed with a first T-DNA contained a second unselected T-DNA, were approximately 40% reproducible, irrespective of the selection, the transformation frequency, and the plant system used. Extrapolation of these results suggests that at least two independently transferred T-DNAs were present in 64% of the transformed plant cells. Molecular analysis of cocultivated N. tabacum shoots regenerated on nonselective medium showed that only a few transformants had a silenced (2/46) or truncated (1/46) T-DNA. Therefore, most integrated T-DNAs expressed their selectable or screenable markers in primary transgenic plants. Remarkably, 10 to 30% of the selected A. thaliana shoots or progenies lost the T-DNA marker they were selected on. As these regenerants contained the unselected T-DNA with a high frequency (17%), these selected plants might result from the expression of unstable, transiently expressed T-DNAs. In conclusion, a significant part of the T-DNAs is lost from the transformed cells.

Nonimmune hydrops fetalis due to congenital syphilis associated with negative intrapartum maternal serology screening

We present an unusual case, in which a woman presenting with markedly decreased fetal movements at 29 weeks gestation following a recent increase in fundal height was noted sonographically to have fetal hydrops consisting of scalp edema, marked hepatomegaly, ascites, and polyhydramnios. No lethal structural congenital anomaly was noted. Admission laboratory examinations revealed a negative antibody screen and a negative RPR. Emergent cesarean section was performed due to prolonged fetal bradycardia during biophysical profile testing. The acidotic hydropic neonate weighing 1825 g was resuscitated yet succumbed at 3 hr of life following intravenous administration of antibiotics. Neonatal blood was RPR positive at 1:16. Postmortem pathology examination demonstrated severe multiorgan system failure secondary to overwhelming congenital syphilis. Extensive extramedullary hematopoiesis was noted and histopathology with Dieterle stains revealed numerous hepatic spirochetes. Postpartum reexamination of the maternal blood with serial dilutions revealed a positive RPR at 1:1024. This case emphasizes that initial negative screening for syphilis may be seen despite overwhelming infection, a condition that has been termed the "prozone effect."